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SELECTED ARTICLES. 
other chemists, and in what points I differ, especially with 
M. Malagutti, with whom, however, it is probable I should be 
more in unison, if he had operated comparatively on the seve- 
ral varieties of grape sugar. 
Twenty-nine grammes of cane sugar were dissolved in fifty 
grammes of water, acidulated with five grammes of sulphuric 
acid, the whole was boiled in a water bath, at the same time 
with a similar mixture in which sugar of starch replaced that 
of the cane. A few minutes boiling were sufficient to cause 
a deposit of ulmic acid in the flask containing the cane su- 
gar, whilst the solution of the starch sugar was scarcely co- 
loured; but, after boiling for an hour, both flasks contained a 
deposit. The quantity of acid was too great in this experi- 
ment. I dissolved in several flasks, each containing fifty 
grammes of water and one of sulphuric acid; 1st, ten grammes 
of cane sugar; 2d, ten grammes of crystallized grape sugar, pro- 
cured by the action of sulphuric acid on cane sugar; 3d, ten 
grammes of crystallized grape sugar, obtained from raisins; 4th, 
ten grammes of crystallized grape sugar, arising from the action 
of sulphuric acid on fecula. The deposit of ulmic acid began 
to form after a few minutes' boiling, in the first flask; and 
soon afterwards occurred in the second; a longer time elapsed 
before it became visible in the third; whilst in the fourth a 
few flakes only were perceptible after an ebullition of six 
hours. This experiment was variously modified by augment- 
ing and diminishing the proportion of acid, always operating 
comparatively in the same water bath, and it was found that 
the formation of ulmic acid followed an invariable order; 1st, 
cane sugar; 2d, grape sugar, procured by the action of sul- 
phuric acid on cane sugar; 3d, grape sugar; 4th, and differing 
essentially, sugar from starch. This experiment is remarkable, 
as it proves that when the decomposing effect of the sulphuric 
acid has been arrested for some time, as regards cane sugar, 
it afterwards operates on it much more slowly than if it had 
exercised a continued action. The elements become arranged 
in a more settled manner, and thus are better enabled to re- 
sist the operation of the acid. It also demonstrates that well 
